Besides for the extreme ease of documentation (which is getting a little harder now that there's so many different services), Stripe gained a lot of traction at

Besides for the extreme ease of documentation (which is getting a little harder now that there's so many different services), Stripe gained a lot of traction at the start. Stripe was one of the first credit card acceptance companies with $0 monthly fees. I was paying a merchant account monthly, then authorize.net gateway fee, then an extra $20 to authorize.net to store tokens. Then the per-card fees were somewhat opaque with every card (qualified vs non-qualified) having different pricing. With stripe, it became much lower risk: pay a set fee for each transaction. No monthly minimums. Many of the credit card companies have moved to this model, but it was rather cutting edge and seemed much more "fair" for a commoditized gateway.